MSL and W3C XML Schema

[Jonathan Robie <Jonathan.Robie@SoftwareAG-USA.com>]

A recent xmlhack article (http://www.xmlhack.com/read.php?item=1097) gave 
me a little more credit than I can legitimately accept, and was somewhat 
misleading about the relationship between XML Schema and MSL.

I would like to respond to the following paragraph:

>It is clear that W3C XML Schema in its current form will not be acceptable 
>to a large part of the XML developer world (as well as several members of 
>its own Working Group). Difficulties with XML Schema's lack of an 
>underlying mathematical model recently led XML Query WG members Jonathan 
>Robie, Phillip Wadler and colleagues to develop Model Schema Language 
>(PDF), essentially an attempt to retrofit a mathematical model to W3C XML 
>Schema.

First off, a great deal of the work on MSL was done by Matthew Fuchs of 
Commerce One and Allen Brown of Microsoft, and the original name was 
"Matt's Schema Language", though we decided to make it sound a bit more 
formal. So I felt that it was just a unfair to reduce Matthew and Allen to 
the phrase "and colleagues".

Second, of the four MSL authors, three are members of the XML Schema 
Working Group, and three are members of the XML Query Working Group. One of 
the big reasons for MSL was to provide a simpler, formal basis for a query 
language type system, which was a major motivation for those of us 
interested in query languages. The response of the XML Schema Working Group 
was to accept formalization as an exit criterion for their Candidate 
Recommendation phase, which will provide XML Schema with a mathematical 
model. I think that the XML Schema Working Group should be commended for 
agreeing to this. The ongoing work in XML Schema formalization is being 
done in the XML Schema Working Group itself.

Jonathan